That problem is so bad that you don’t need to worry about the problem of who raised these young adults, which is supposed to be the issue in the first place.

They live with their parents. But for how long have they done that, and for how long have their parents been in gay or lesbian relationships? We can’t know. Allen controls for whether the child has moved in the last year or five years, but we don’t know if the parents moved with them. Controlling for whether they have moved doesn’t address this. A full 60% of the lesbian-mother kids and 39% of the gay-father kids have moved in the last five years, compared with just 24% of the different-sex-married-parent kids. Their life stories are in these mobility histories, and the paper can’t say anything about that.

This has been seized upon by those who are very nervous about the growing acceptance of same-sex marriage as proof that it can harm innocent children.

Except. There are no Canadian children old enough to have graduated from high school who have lived their entire lives in a household headed by two women — or two men — who are married to each other. Same-sex marriage has only been legal in Canada since 2005.

Compare the graduation success of children raised in cohabitating opposite-sex households to those raised in same-sex households, and the difference all but evaporates. Come back in 20 years, when a significant cohort of children of same-sex households have been raised in unions cemented by marriage, and we’ll talk.

Or maybe we won’t. Since when do we base our acceptance of other people on statistical models?

Blacks drop out of high school at higher rates than whites. Hispanics drop out at higher rates than blacks. So do we just stop trying to educate blacks or Hispanics? Do we try to prohibit blacks and Hispanics from reproducing, in marriage or out?